A man who was wearing only his underwear and socks was charged with misdemeanor DUI after he struck a squad car Saturday morning on the city's Northwest Side.

About 11 a.m., a concerned citizen alerted police to a possible drunk driver driving in an alley on the 2800 block of North Kostner Avenue, said Chicago Police Department News Affairs Officer John Mirabelli. The man was using the alley as a through street, he said.

The man, driving a black 2010 Honda, was spotted by police on the 4000 block of West Diversey Street where they made a call for assistance.

The man eventually drove the wrong way on a one-way street on the 2900 block of North Kilbourn Avenue in the Belmont Gardens neighborhood and crashed into a squad vehicle that was assisting in the call, Mirabelli said.

After the crash, the man opened the door and fell out of the car wearing only underwear and socks, he said.

He was taken to Our Lady of the Resurrection Medical Center where he was treated for minor scrapes to his face.

The driver, identified as Arsenio Garcia, 24, of the 4000 block of West Potomac Avenue, was charged with misdemeanor DUI, using an alley as a through street, driving the wrong-way down a one-way street, no license, no insurance, failure to reduce speed and damage to public property, Mirabelli said.

The officer in the squad car suffered minor injuries and was taken to a local hospital where he was treated and released.